Cable equalizer for elevators



R.. P. HIGBEE CABLE EQUAL IZER FOR ELEVATORS Flled Sept 30, 1927 Jan.29, 1929.

INVENTOR 541/ P Hiybee T'i' RNEY Patented Jan. 2a, 1929.

RAY P. HIGBEE, or PrrILAnnLriara, rniamsyrverna.Assrsuon To wrisamaueusnELECTRIC &. MAnUrAo'i-Umne GOMEANY, .a eonren-A'rmnor PENESYLVANIA-CABLE EQUALIZER FOR ELEVATORS.

Application filed es -amber 30, 1-927. Serial No. 223,011.

My invention relates to equalizers for distributing a load drawn by orsupported by a plurality'of drawing or supporting devices in such mannerthat each of the drawing or supporting devices will receive an equalamount of the load. invention has special reference to equalizers forelevators, hoists and similar machinery wherein the load is supportedupon a plurality ofcables.

An objectof my inventionis to provide a device for distributing thetotal load equally 1 between a plurality of draft devices.

Another object of my invention is to provide a cable equalizer for theabove stated purposes which is simple in construction, and has a minimumof parts. 7

Another object of my invention is to provide a cable equalizer systemforelevators wherein the distribution of the load upon each of thecables is achieved by a division of load, both at the counterweight andat the elevator cab structure. v

My invention will be described with referonce to the accompanyingdrawing, where-- in 4 Figure 1 is a perspective View of a portion of mycablebqualizing device attached to the superstructure of the elevatorcab,

Fig. 2 is an end view of the assembly of my cable-equalizing deviceattached to the superstructure of the elevator cab; and r Fig. 3 is aside elevation of'a cable-equalizing device which I propose to use onthe elevator counterweight.

In modern elevator equipment, it is usual to employ a cab of such weightand designed to carry such loads that it is not feasible to support thecab structure upon a single cable. Hence, it has long been the practiceto use a number of supporting cables, ranging from 2 to 8 or more cablesper elevator. These cables are attached to the supporting structure ofthe elevator cab andare tensioned when installed to equalize the loadupon the several cables. This tensioning is extremely inaccurate at theinitial installation of the cables, since the only manner in which thetension may be tested is to compare the resistance to turning of thelocking nuts as each of the cables is drawn taut.

It is well known that after a few days service the cables stretch totheir extreme normal length, after which any further stretching isdependent upon theweight placed upon the cab and the elasticity of thecables. This initial stretching is not uniform in allcof the cables,varying between the several cables in extreme degrees. Thus, a'few daysafter installation of cables, thetens'ion on each of the cables hasundergone a great change, regardless of the care which may have beentaken in the initial installation.

' The result of the change in the tensioning of the cables as previouslydescribed is that one of the cables is tensioned to a greater amountthan the others and the'tension of each cable varies with reference tothe remainder, so that only one or two out of a total of 4, 6 or'8cables does the actual work of supporting the load.

' Various devices have been designed time to time to overcome this fault'an-dto automatically'adjust the load upon the cables the stretchingoccurs. "However, these devices usually comprisea complicated system oflevers, rollers or other devices, the cost of manufacture and thedelicacy of adjustment of which render their use impracticable.

Ipropose to use a simple system of levers based upon the well-knownprinciple'of moments of force varying according as the load is placedcloser to, or farther from the fulcrum.

Referringto Fig. 1, I have'illustrateda portion of the structure of anelevator cab,

ordinarilycomprising a pair of spaced apart channel irons, one of whichis designated as l 1 and shown in full lines, the other of which isdesignated as 2' and is shown'in dotted lines. These spaced apartchannel irons extend across the top of the elevator cab and haveattached thereto the remainder of the supporting structure {not shown)for the.

elevator cab platform in a manner wellknown in the elevator art. Anopening 3 in the channel iron member 2 receives therethrough asupporting bar 4 which extends through a similar, alinedopening 5 in theother channel member 1. Between the two channel members 1 and 2', thesupporting bar 4 passes through openings in each of two telescopingequalizing members designated as 6 and 7.

The equalizing member 7 comprises a U- .shaped element having a solidportion 8 and two relatively'narr-ow legs 9 and 10 extend- The otherequalizing member 6 comprises an elongated member formed of squaredstock and is provided with tapered openings 17 and 18 near the ends ofthe bar, which openings correspond in form to the opening 12.

in the member 7. The bar 6 is also provided with spaced apart openings19 and 20 extending in a plane at right angles to the openings 1'7 and18. The distance between the openings 19 and 20 is the same as thedistance between the openings 13 and 15 and 1A and 16 in the legs 9 and10, respectively, of the bar 7. i

The supporting bar i extends through the opening 16 in leg 10, theopening 20 of member 6 and. the opening 15 in leg 9, and in this mannerconnects the equalizing member 7 in su ortin en a ement with channeliron b 21 6 members 1 and 2 and with equalizing member 6. It will benoted that the opening 20 is formed in oval cross section, slightlylarger than is necessary to fit the supporting bar l,

thus permitting a slight vertical movement between the members-6 and 7.A connecting bar 21 extends through the alined openings 14 and 13 or themembers 10 and 9 and also through the opening 19 of the member 6, thuspivotally connecting the extending legs 9 and 10 with the member 6.

It will be noted that the connecting bar 21 extends only so far as isnecessary to pass through the members 9, 10 and 6, and does not extendinto engagement with either of channel members, 1 and '2.

As a means of attaching the cables to the equalizing bars, a bolt 22 isinserted through the opening 12 in the member 7 and is secured in theopening by any suitable means, represented as a pair of nuts 23 and 2st.The nut 23 acts as a head tor the bolt while the nut 24 engaging the nut23 serves as a locknut to prevent the nut from becoming loosened, whensubjected to the usual shocks occasioned by movements of the elevatorcab.

The upper portion of the bolt 22 is formed with a bolt head 25 extendingthrough an opening inthe strap 26 of a clevis 27, to which the elevatorsupporting cable 28 is at tached in any well known manner. Thisarrangement of clevis and cableis well known in the art and does notform any part of. my invention. r

Assuming, for example, that an elevator cab of such proportions andweight as to re quire the use of six cables, my device may be used todistribute the total weight of the cab equally between each of the sixcables. Referring to Fig. 3, the cables, designated by the characters A,B, C, D, E and F, are secured to the counterweight 29 by means of apivotally connected equalizing bar 30. The bar 30 is suitably supportedupon the counterweight structure 29 by means of a pair of brackets 31,(only one of which is shown) through which passes a supporting pin 32,which also passes through an opening 33 in the equalizing member 30.

The supporting cables A, B, C, D, E and F are divided into groups ofthree, one group comprising the cables A, B and C attached to theequalizing bar 30 upon one side of the supporting pivot pin 32 insuitably tapered openings in the bar 30, such openings being designatedby the reference numerals 34, 35 and 36. The c bles A, B and C are eachsecured by a bolt, nut and clevis structure similar to that describedwith reference to Figs. 1 and 2. The remaining cables D, E and F aresecured in suitable openings 37, 38 and 39 upon the end of the bar 30opposite to that to which the first three cables are secured.

By suitably spacing the openings 36 and 37 at equal distances from thecenter of the supporting pivot pin 32, an equal distribution of the loadof the counterweight may be secured. By corresponding equal spacing ofthe openings 35, 38 and 34, 39, the load may be distributedequallybetween each of the two groups of cables, A, B, C, and D, E, F.

It is obvious, however, that the load be tween cables A, B and C willnot be equal with this arrangement and this unbalancing of load iscompensated for by the use of the second portion of my equalizingstructure, on the elevator cab.

By reference to Fig. 2, it will be readily seen that the completeassembly for the. assumed number of cables necessitates the use of twoof the structures shown in 1, one for each group of three'cables. Assumethe use of two such structures, one of which, designated generally bythe numeral 40, will act asa seeming device for one of the groups ofcables, for example, A, B and C, while the other of the structures,designated generally by the numeral 1-1, may be used to secure theremaining group of cables D, E and F.

The arrangement of the cables may be such that the cable A willbesecured at the opening 17 in the member 6, the cable B may be secured inthe opening 18 of the member 6 and the cable C in the opening 12 of themember 7. By properly spacing the opening 17 l a distance (X) from thecenter, or fulcrum point, of the connecting bar 21, equal to thedistance (Y) between the opening 18 and the center of the bar 21,- it isreadily by application of the simple principle of levers, that an equaldistribution of the load between the cables A and B will be secured. Ifthe distance (ltd) between the center of the supportingbar a (thefulcrum "for member?) and the opening 12 is made twice that of thedistance (Nlbetween the center of the supporting bar 4 and the center ofthe connecting bar 21,11. further equal distribution ofthe load betweenthe cable C and each of the cables A and B will be accomplished. Thus,half the combined counterweight and elevator cab structure. load (halvedby the use of the equalizer on the counterweight) will be distributedequally between the cables A, B and C. I

By a similar location of the cables, D, E

and F on the structure 4:1,a similar distribu-.

tion of half the total load equally between each of these three cableswill be achieved. Thus, the total load of the counterweight and cab willbe equally distributed between each of the six cables, each cablesupporting but one-sixth of the load."

In the event of a stretching of one of the cables with reference to theother, the equalizing bar to which it is attached may rotate about itspivot without varying the load upon any of the remaining cables. Theelongation of either of cables A and B, causing the rotation of themember 6, will not cause any variation of the load upon cable C, byreason of the fact that the enlarged opening 20, through which thesupporting pin 4 passes, by acting as a pivot for the supporting bar 7will permit the bar 6 to rotate without changing theposition of themember 7. Similarly, elongation of the cable C, causing the rotation ofthe member 7' about its pivot a, will move the member 6 slightlyupwardly, slackening the cables A and B to thus restore equal tensionupon the three cables.

It is thus seen that n y device may be used to equally divide the loadbetween the several cables in an elevator system, placing an equalstrain upon each of the cables. It is well recognized in the elevatorart that the unequal tensioning of the several cables causes one or moreof the cables to wear more rapidly than the remainder; but the use of mydevice will prevent this undue wear upon any one of the cables and willthus increase the life of the entire set. Moreover, by equalizing thestrain on each of the cables, the danger of cable breakage is obviated,thus rendering the elevator using'my device more safe in operation.

l/Vhile I have illustrated my device in combination with a system of sixcables, it is readily seen that by a suitable selection of the numbersand arrangement of the pieces of apparatus shown in Figs. 1 and 2, mydevice may be adapted for use with any'number of cables, either an oddnumber or an even numbet. Itlereevearhe number of parts n eces-s saryfor the-use ofmy device is relatively small and the constructionextremely simple.

The embodiment of mydevice shown is merelyillustrative and I do notdesire to be on each of said groupsequally between the cables of saidgroups.

2. I11 :1. cable equalizer for an elevator supported by a plurality ofcables and substantially balanced by acounterweight,means at saidcounterweight for dividing the load equally between a plurality ofgroups of said cables, and means at said elevator for each of said 1groups for dividing the load on each group equally between groups. i V v3. In a cable equalizer for a system of the type wherein two members aresupported in substantially balanced relation to each other by aplurality of cables, means at one of said members for dividing the totalload equally between a plurality of groups of said cables, each of saidgroups comprising a plural odd number of said cables, and means at theother of said members for each of said the cables of said 7 groups fordividing the load on each of said groupsequally between the cablesojfsaid group.

4. In a device for distributing a load be tween a plurality ofload-supporting devices, means for dividing the load equally between aplurality of groups of said supporting devices, each of said groupscomprising three of said supporting devices, means for dividing the loadequally between each of the supporting devices in each of said groupscompris-f ing a lever, a fulcrum for, said lever, means for attachingone of said load-supporting devices to said lever at oppositesides ofsaid fulcrum, a second lever, a fulcrum for said second lever, means forattaching the load to the fulcrum of said second lever, means forattaching one end of said second lever to the fulcrum of said firstlever, and means for attaching the third of said load-supporting devices t0 the opposite end of said second lever at a distance from thefulcrum of said second lever equal to twice the distance between thefulcrums of said levers. y

5. In a device for distributing a load" equally between threeload-supporting devices, a lever,a fulcrum for said lever, means forattaching said supporting devices on o posite sides of said fulcrum andat equal distances from said fulcrum, a second lever, on said secondlever equal to one third of the means for attaching one end of saidsecond distance between thepoint of attachment of lever to the fulcrumof said first lever, means said third supporting devices and the pointfor attaching the third of said supporting deof attachment of said firstlever. vices to the other end of said second lever, In testimonywhereofflhave hereunto suband means for attaching the supported loadscribed my name this 19th day of August,

at the fulcrum of said second lever, said last 1927.

mentioned fulcrum beinglocated at a point RAY 1. HIGBEE.

